A radiocommunication apparatus, a radiocommunication system, and a radiocommunication method adapted to a radio network system for attaining synchronism of a reception signal, which contains a plurality of synchronism attainment signals representing the same pattern of bits, relative to a reference signal, in which the autocorrelation function of the reception signal and the cross-correlation function thereof are detected, and the synchronism attainment signals contained in the reception signal are detected based on the detected autocorrelation function and cross-correlation function. Consequently, a receiving side can reliably detect the synchronism attainment signals.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A radiocommunication apparatus for attaining the synchronism of a reception signal, which contains a plurality of synchronism attainment signals representing the same pattern of bits, relative to a reference signal, said radiocommunication apparatus comprising: an autocorrelation detection circuit for detecting the autocorrelation function of the reception signal; a cross-correlation detection circuit connected in parallel with the autocorrelation detection circuit for detecting the cross-correlation function of the reception signal simultaneously with the detecting of the autocorrelation detection circuit; and a synchronism attainment circuit for detecting the synchronism attainment signals contained in the reception signal based on the detected autocorrelation function from the autocorrelation detection circuit and on the detected cross-correlation function from the cross-correlation detection circuit, and thus attaining the synchronism.
2. A radiocommunication apparatus according to claim 1 , further comprising a demodulation circuit for demodulating the reception signal with the synchronism attained by said synchronism attainment circuit maintained.
3. A radiocommunication apparatus for attaining the synchronism of a reception signal, which contains a plurality of synchronism attainment signals representing the same pattern of bits, relative to a reference signal, said radiocommunication apparatus comprising: an autocorrelation detection circuit for detecting the autocorrelation function of the reception signal and outputting an autocorrelation signal; a cross-correlation detection circuit for detecting the cross-correlation function of the reception signal and outputting a cross-correlation signal; a mask circuit for masking a predetermined component of the cross-correlation signal according to the autocorrelation signal; and a synchronism attainment circuit for detecting the synchronism attainment signals contained in the reception signal according to the masked cross-correlation signal, and thus attaining the synchronism.
4. A radiocommunication apparatus according to claim 3 , wherein said synchronism attainment circuit compares the masked cross-correlation signal with a predetermined threshold to detect the synchronism attainment signals.
5. A radiocommunication apparatus according to claim 3 , wherein said synchronism attainment circuit specifies a maximum level exhibited by the masked cross-correlation signal to detect the synchronism attainment signals.
6. A radiocommunication apparatus according to claim 3 , wherein said synchronism attainment circuit judges whether the masked cross-correlation signal has exceeded a predetermined threshold, specifies a maximum level exhibited by the cross-correlation signal from among all the levels exhibited thereby and exceeding the threshold, and thus detects the synchronism attainment signals.
7. A radiocommunication apparatus according to claim 3 , wherein said synchronism attainment signals represent data encoded according to a pseudo spreading code.
8. A radiocommunication apparatus according to claim 3 , wherein said synchronism attainment signals are signals modulated in conformity with the OFDM method.
9. A radiocommunication apparatus according to claim 3 , further comprising an error correction circuit for when the reception signal contains a signal representing an error correcting code to be used to check at least part of data represented by the reception signal, corrects an error in the part of the data using the error correcting code.
10. A radiocommunication apparatus according to claim 3 , wherein said plurality of synchronism attainment signals are contained in the reception signal in units of one transmission period.
11. A radiocommunication apparatus according to claim 3 , further comprising a demodulation circuit for demodulating the reception signal with the synchronism attained by said synchronism attainment circuit maintained as a reference.
12. A radiocommunication system comprising: a transmitting apparatus, said transmitting apparatus including: a signal production circuit for producing a signal that contains a plurality of synchronism attainment signals representing the same pattern of bits, and transmitting means for transmitting the produced signal; receiving means for receiving the signal transmitted from said transmitting means; an autocorrelation detection circuit for detecting the autocorrelation function of the received signal; a cross-correlation detection circuit connected in parallel with the autocorrelation detection circuit for detecting the cross-correlation function of the received signal simultaneously with the detecting of the autocorrelation function by the autocorrelation detection circuit; and a synchronism attainment circuit for detecting the synchronism attainment signals contained in the received signal based on the detected autocorrelation function from the autocorrelation detection circuit and on the detected cross-correlation function from the cross-correlation detection circuit, and thus attaining the synchronism of the received signal relative to a reference signal.
13. A radiocommunication system according to claim 12 , wherein said signal production circuit included in said transmitting apparatus produces a modulated signal that contains a plurality of successive synchronism attainment signals representing the same pattern of bits.
14. A radiocommunication method for attaining the synchronism of a reception signal, which contains a plurality of synchronism attainment signals representing the same pattern of bits, relative to a reference signal, said radiocommunication method comprising the steps of: detecting the autocorrelation function of the reception signal; detecting the cross-correlation function of the reception signal simultaneously with the step of detecting the autocorrelation function; and detecting the synchronism attainment signals,contained in the reception signal based on the detected autocorrelation function detected in said step of detecting the autocorrelation function and based on the detected cross-correlation function detected in the step of detecting the cross-correlation function, and thus attaining the synchronism.
15. A radiocommunication method according to claim 14 , further comprising a step of demodulating the reception signal with the attained synchronism maintained as a reference.
16. A radiocommunication method for attaining the synchronism of a reception signal, which contains a plurality of synchronism attainment signals representing the same pattern of bits, relative to a reference signal, said radiocommunication method comprising the steps of: detecting the autocorrelation function of the reception signal and outputting an autocorrelation signal; detecting the cross-correlation function of the reception signal and outputting a cross-correlation signal; masking a predetermined component of the cross-correlation signal, which represents the cross-correlation functions of samples of the reception signal including the cross-correlation functions of the synchronism attainment signals, according to the autocorrelation signal; and detecting the synchronism attainment signals contained in the reception signal according to the masked cross-correlation signal, and thus attaining the synchronism.
17. A radiocommunication method according to claim 16 , wherein the synchronism attainment signals are detected by comparing the masked cross-correlation signal with a predetermined threshold.
18. A radiocommunication method according to claim 16 , wherein the synchronism attainment signals are detected by specifying a maximum level exhibited by the masked cross-correlation signal.
19. A radiocommunication method according to claim 16 , wherein the synchronism attainment signals are detected by judging whether the masked cross-correlation signal has exceeded a predetermined threshold, and specifying a maximum level exhibited by the cross-correlation signal from among all the levels exhibited thereby and exceeding the threshold.
20. A radiocommunication method according to claim 16 , further comprising a step of demodulating the reception signal with the attained synchronism maintained as a reference.
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November 20, 2000
August 3, 2004
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